Head slider

ABSTRACT

The head slider mounts a recording/reproducing element and flies over a recording medium with the airflow generated when the recording medium moves. The head slider comprises a slider body having an air inflow end and an air outflow end, a rail projected from the slider body to define an air bearing surface extended to the outflow end, a projection formed on the rail and between the inflow end and the outflow end, and a recess formed at the outflow end of the rail to make narrow the width of the rail. When the recording medium stops, the head slider and the recording medium are in contact at the projection and the air outflow end of the rail. Since the outflow end of the rail is narrow in width, the stiction can be prevented. Moreover, it is unnecessary to form a projection near the outflow end of the rail and thereby the flying height of the recording/reproducing element can be lowered to improve the recording/reproducing sensitivity.

FIELD OF THE INVENTION

[0001] The present invention relates to a head slider which is used in amagnetic disk drive or the like. The head slider mounts arecording/reproducing element and is also arranged on a recording mediumto fly over the recording medium owing to the airflow generated bymovement of the recording medium.

[0002] In more specific, the present invention relates to a head sliderhaving projections at the sliding surface, which are suitable foravoiding the stiction between the head slider and the recording medium.

BACKGROUND OF THE INVENTION

[0003] FIGS. 1(a)-(c) show a magnetic head slider of the prior art. Inthe prior art, the magnetic head slider has floating rails 41 and 42, inthe longitudinal direction, just opposed to a magnetic disk 3 when it isbuilt into a magnetic disk drive. The magnetic head slider flies overthe magnetic disk 3 when the airflow generated by rotation of themagnetic disk 3 enters into an air inflow end 5 and affects the floatingrails 41-43, and then conducts the recording/reproducing operation toand from the magnetic disk 3 with an electromagnetic transducer 2arranged at the area near the air outflow end 7.

[0004] It is effective to reduce the contact area of the magnetic headslider in order to prevent the stiction at the time of contacting with aCSS (Contact Start Stop) zone, therefore, projections 61-64 are providedon the rail surfaces of the floating rails 41 and 42. As shown in FIG.1(b), in order to effectively prevent the stiction while the projections61-64 are contacting with the magnetic recording, the height H of theprojections 61-64 must be necessarily at least 20 nm for the magneticdisk 3 having Ra (average roughness) of about 2 nm. It has been verifiedexperimentally that the stiction cannot be prevented if the height H isless than such value.

[0005] However, the prior art explained above has followingdisadvantages. The magnetic head slider takes a flying condition thatthe flying height of the air inflow end 5 is higher than one of the airoutflow end 7 as shown in FIG. 1(c). If the electromagnetic transducer 2is attempted to be located near the magnetic disk 3 by reducing theflying height δ of the magnetic head slider in view of enhancing therecording/reproducing sensitivity, the projections 63 and 64 near theair outflow end 7 may interfere with the surface of the magnetic disk 3.Moreover, in order to prevent the interference of the projections 63 and64, it is thought to set up the pitch angle of the magnetic head slider,but it is disadvantage in the viewpoint of balance of the fryingcondition.

DISCLOSURE OF THE INVENTION

[0006] It is an object of the present invention to provide a head slidersuitable for preventing the stiction to a recording medium.

[0007] It is another object of the present invention to provide a headslider which realizes the small flying height while preventing thestiction to a recording medium.

[0008] It is further object of the present invention to provide a headslider which achieves the small flying height and improves therecording/reproducing sensitivity to a recording medium.

[0009] The objects explained above can be achieved by a head sliderwhich mounts a recording/reproducing element and flies over therecording medium with the airflow generated when the recording mediummoves. This head slider comprises a slider body having the air inflowend and an air outgoing end, a rail which is projected from the sliderbody to define an air bearing surface extended to the outflow end, aprojection formed on the rail and between the inflow end and the outflowend, and a recess formed at the outflow end of the rail to make narrowthe width of the rail.

[0010] According to the present invention, when the recording mediumstops to move, the head slider and the recording medium are in contacteach other at the projection and the air outflow end of the rail. Sincethe air outflow end of the rail is rather narrow in width, the stictioncan be prevented. Moreover, it is no longer required to form aprojection near the outflow end of the rail and therefore the flyingheight of the recording/reproducing element can be lowered to improvethe recording/reproducing sensitivity.

[0011] According the other aspect of the present invention, the width ofthe recording/reproducing element at the surface opposed to therecording medium is narrower than the width of the outflow end of therail. According to this aspect, the recording/reproducing element isnever exposed to the side wall of the recess of the rail and thereby thecorrosion of the recording/reproducing element can be prevented.

[0012] According to still another aspect of the present invention, therail comprises a couple of rails, and the width of one rail, where therecording/reproducing element is formed, at the outflow end is widerthan the corresponding one of the other rail. According to this aspect,the width of the outflow end of the one rail is set so that therecording/reproducing element is never exposed. Moreover the width ofthe outflow end of the other rail can be set so that the stiction neveroccurs.

[0013] Moreover, according to still further aspect of the presentinvention, the recess isolates an area, where the recording/reproducingelement is formed, from the air bearing surface of the rail and therebythe area is formed like an island. According to this aspect, thephenomenon that the lubricant creeps up can be prevented, therefore, thestiction can be prevented effectively.

[0014] Moreover, according to still further aspect of the presentinvention, a forward projection and a backward projection are providedon the rail. According to this aspect, the area in which the head slideris in contact with the recording medium can be reduced, therefore, thestiction can be prevented effectively. Namely, the head slider is incontact with the recording medium in the following three condition,first the inflow end and the forward projection, secondly the forwardprojection and the backward projection, and thirdly the backwardprojection and the outflow end are in contact with the recording medium.Even in any type of contact condition, the contact area between the headslider and recording medium can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] FIGS. 1(a)-(c) show a head slider of the prior art.

[0016]FIG. 1(a) is a front elevation viewed from a side of the floatingrail forming surface,

[0017]FIG. 1(b) is a side elevation illustrating the contactingcondition to the magnetic disk, and

[0018]FIG. 1(c) is a side elevation illustrating a flying condition.

[0019] FIGS. 2(a)-(c) show a head slider of the present invention.

[0020]FIG. 2(a) is a front elevation viewed from a side of the floatingrail forming surface,

[0021]FIG. 2(b) is a side elevation illustrating the contactingcondition to the magnetic disk, and

[0022]FIG. 2(c) is a cross-sectional view along the line 1C-1C of FIG.2(b).

[0023] FIGS. 3(a)-(c) show an electro-magnetic transducer.

[0024]FIG. 3(a) is a front elevation viewed from a side of the airoutflow end,

[0025]FIG. 3(b) is a cross-sectional view along the line 2B-2B of FIG.3(b), and

[0026]FIG. 3(c) is a cross-sectional view along the line 2C-2C of FIG.3(a).

[0027] FIGS. 4(a) and 4(b) show a modification example of theelectromagnetic transducer.

[0028]FIG. 4(a) is a front elevation of the electro-magnetic transducerviewed from a side of the air outflow end, and

[0029]FIG. 4(b) is a cross-sectional view along the line 3C-3C of FIG.4(a).

[0030]FIG. 5 shows a head slider of the second embodiment of the presentinvention.

[0031]FIG. 6 shows a head slider of the third embodiment of the presentinvention.

[0032] FIGS. 7(a)-(c) show a header slider of the fourth embodiment ofthe present invention.

[0033]FIG. 7(a) is a front elevation viewed from a side of the floatingrail forming surface,

[0034]FIG. 7(b) is a side elevation illustrating the contactingcondition to the magnetic disk, and

[0035]FIG. 7(c) is a side elevation illustrating the flying condition.

[0036] FIGS. 8(a) and 8(b) show the process of manufacturing a thin filmmagnetic head.

[0037]FIG. 8(a) is a perspective view of a wafer, and

[0038]FIG. 8(b) is a perspective view illustrating a condition where abar is cut out.

[0039] FIGS. 9(a)-(e) show the process of forming the floating rail.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0040] FIGS. 2(a)-2(c) show a head slider of the present invention. Amagnetic head slider is manufactured by forming an electro-magnetictransducer 2 on slider body 1 using the thin film process and by formingfloating rails 41-43 on the surface opposing to magnetic disk 3. Thefloating rails are formed of a couple of side rails 41 and 42 and acenter rail 43. The slider body 1 is formed, for example, ofalumina-titanium-carbide (Al₂O₃TiC).

[0041] The magnetic head slider flies over the magnetic disk 3 at thepredetermined height with the airflow in the direction of an arrow markA in FIG. 2(b) due to the rotation of the magnetic disk 3. Moreover, themagnetic head slider has a sloping surface 8 at the air inflow end 5 ofthe slider body 1 and the floating rails 41 to 43.

[0042] The projections 61 and 62 are formed at the boundary between thesloping surface 8 and a rail surface 8′ of the floating rails 41 and 42,and are projected toward the magnetic disk 3. With respect to the sizeof the projections 61 and 62, the contacting area to the magnetic disk 3are as small as not causing the stiction and are as large as not beingworn out easily due to the friction with the magnetic disk 3. Forexample, the projections 61 and 62 are formed as an elongated columnhaving the minor axis length of about 50-70 μm, while the width of thefloating rails 41 and 42 is about 300 μm.

[0043] As explained above, the projections 61 and 62 are required tohave the sufficient height to show stiction-free, for example, about 20nm in minimum or about 30 nm assuming a margin for the magnetic disk 3having the surface roughness Ra of about 2 nm. In FIGS. 2(a) and 2(b),the projections 61 and 62 are formed at the boundary between the slopingsurface 8 and the rail surface 8′ but these may also be formed on onlythe rail surface 8′.

[0044] FIGS. 3(a)-(c) show the electromagnetic transducer. In thesefigures, the electro-magnetic transducer 2 is a composite type headwhich is generally called an MR head and which is formed integrally ainductive element for recording and a magneto-resistive element forreproducing. The electro-magnetic transducer 2 is formed by utilizingthe thin film process and the magneto-resistive element and theinductive element are formed in this sequence from the side of sliderbody (substrate) 1.

[0045] The magneto-resistive element is composed, as shown in FIGS. 3(b)and 3(c), of a magneto-resistive layer (MR layer) 2 f, a non-magneticgap layer 2 a formed for surrounding the MR layer 2 f, and an uppermagnetic shield 2 c and a lower magnetic shield 2 d formed forsandwiching the MR layer 2 f and the gap layer 2 a.

[0046] The inductive element is composed of a lower magnetic pole (theupper shield) 2 c, an upper magnetic pole 2 b, a non-magnetic gap layer2 a′ for forming an interval between the upper and lower magnetic poles2 b and 2 c and at the rail surface, a non-magnetic insulating layer 2 iformed between both magnetic poles 2 b and 2 c, and a coil 2 e formed inthe non-magnetic insulating layer 2 i.

[0047] In the electromagnetic transducer 2, as shown in FIG. 2(b), aprotection film 2 h is formed on the upper magnetic pole 2 b of theinductive element and a protection film 10 a is formed in the floatingsurface side of the inductive element and magneto-resistive element.

[0048] As shown in FIGS. 2(a)-(c), the electro-magnetic transducer 2 isarranged at the air outflow end 7 of the floating rail 41 and a part ofthe electro-magnetic transducer 2 is appearing on the rail surface ofthe floating rail 41. In the floating rail 41, at the air outflow end 7,both sides of the electromagnetic transducer 2 are engraved along thelongitudinal direction of the floating rail 41, and thereby a narrowwidth portion 4 a and recesses 9 are formed.

[0049] Namely, the floating rail 41 is narrowed in width at the airoutflow end 7 for the contact with the magnetic disk 3. When themagnetic disk 3 having the surface roughness Ra of about 2 nm isconsidered, it is desirable that the depth d of the recesses 9 of thefloating rail 41 is 20 nm or more and the width w of the narrow portion4 a is about 50 to 100 μm.

[0050] In this embodiment, when contacting with the CSS zone, theprojection 61 near the air inflow end 5 and the narrow portion 4 a atthe air outflow end 7 are in contact with the surface of the magneticdisk 3 as shown in FIGS. 2(b) and 2(c). The narrow portion 4 a is asnarrow as 50 to 100 μm in width in comparison with the floating rail 4of 300 μm and therefore there is no fear for the stiction to themagnetic disk 3. Moreover, even in the case of the floating condition,since the projection is not provided near the narrow portion 4 a, theflying height from the magnetic disk can be reduced.

[0051] FIGS. 4(a) and 4(b) show a modification example of theelectro-magnetic transducer. In the electromagnetic transducer shown inFIGS. 3(a)-(c), since the floating rail 41 where the elector-magnetictransducer 2 is arranged is engraved, the upper and lower shields 2 cand 2 d are exposed to the side wall of the engraved portion. Therefore,the elector-magnetic transducer 2 potentially has the possibility ofcorrosion.

[0052] This problem can be eliminated, as shown in FIGS. 4(a) and 4(b),by forming the upper and lower shields 2 c and 2 d of theelectromagnetic transducer 2 to such a size as can be accommodatedwithin the narrow portion 4 a. Namely, in this embodiment, the magneticshields 2 c and 2 d are formed so as to have a step that their tipportions opposed to the magnetic disk 3 are narrowed in width, and thefloating rail 41 is engraved at the position adequately isolated fromthe side edge of the magnetic shields 2 c and 2 d. As a result, the sidewall of the narrow portion 4 a is covered with the protection film 2 hwhich is also covering the electromagnetic transducer 2. Thereby, theexposure to the outside can be prevented.

[0053]FIG. 5 shows a head slider of a second embodiment of the presentinvention. For the explanation of the second embodiment, the elementswhich are substantially same as the above-mentioned embodiment aredesignated by the same reference numerals, and the explanation isomitted here. In this embodiment, the width w1 of the narrow portion 4 aof the floating rail 41 where the electromagnetic transducer 2 isarranged is formed wide and the width w2 of the narrow portion 4 a ofthe floating rail 42 where the electro-magnetic transducer 2 is notarranged is formed narrow.

[0054] Since the narrow portion 4 a of the floating rail 41 where theelectro-magnetic transducer 2 is arranged is formed in the width notinterring the magnetic shields 2 c and 2 d, the magnetic shields 2 c and2 d are never exposed to the outside. Therefore, there is no fear forthe corrosion. Moreover, since the narrow portion 4 a where theelectromagnetic transducer 2 is not arranged is formed narrow, incomparison with the first embodiment, as much as the widening of thenarrow portion 4 a of the floating rail 41 where the electro-magnetictransducer is arranged. Therefore, the total contacting area is neverenlarged.

[0055]FIG. 6 shows a head slider of a third embodiment of the presentinvention. This embodiment is a modification for effectively preventingthe stiction. The recesses 9 in both right and left sides of the narrowportions 4 a are coupled with second recesses 9′ crossing the floatingrails 41 and 42. As a result, the narrow portion 4 a is formed like anisland which is capable of preventing that the lubricant creeps up bythe capillarity. The second recess 9′ has the same depth to both rightand left recesses and the width wc of about 5 μm.

[0056] FIGS. 7(a)-7(c) show a head slider of a fourth embodiment of thepresent invention. In this embodiment, each floating rail 41 and 42 isprovided with the backward projections 63 and 64, in addition to theforward projections 61 and 62 in the side of the air inflow end 5. Thebackward projections 63 and 64 as shown in FIG. 7(b) have the height of20 nm or more not to cause the stiction at the time of contacting withthe magnetic disk 3.

[0057] Moreover, it is preferable, as shown in FIG. 7(c) that thebackward projections 63 and 64 are provided at the area so that they arenot in contact with the magnetic disk 3 when the magnetic head sliderflies. In this embodiment, the backward projections 63 and 64 has theheight almost equal to the forward projections 61 and 62 provided nearthe air inflow end 5, and are arranged at the center of each floatingrail 41 and 42.

[0058] Therefore, in this embodiment, since the projection 61-64 are incontact with the CSS zone of the magnetic disk 3 under normal conditionas shown in FIG. 7(b), the contacting area with the magnetic disk 3 canbe reduced and thereby the stiction can be prevented. In addition, evenif the air outflow end 7 is in contact with to the CSS zone as shown bya chain line in FIG. 7(b), the angle Θ to the magnetic disk 3 becomeslarge. Therefore, the contacting area becomes small and the possibilityfor the stiction is also lowered.

[0059] FIGS. 8(a) and 8(b) show the process of manufacturing themagnetic head slider. The magnetic head slider can be obtained byforming a plurality of electro-magnetic transducers 2 on a ceramic wafer10 such as alumina-titanium-carbide (Al₂O₃TiC) using the thin filmprocess as shown in FIG. 8(a), then cutting the wafer by a dicing sawinto bars that the electromagnetic transducers 2 are arranged in a lineas shown in FIG. 8(b), then forming the floating rails 41 and 42 on thecutting surface A of the magnetic pole side of each bar by the processexplained later, and then separating from the bar. If a sloping surface8 as shown in FIG. 2 is formed at the air inflow end 5, the chamferingprocess applies to the edge of the bar after the cutting process of thewafer into the bar and before the forming process of the floating rails.

[0060]FIG. 9 shows the process of forming the floating rails to the bar.First, the floating rails are formed by etching the floating railforming surface (surface A of FIG. 8(b)) of the bar. Thereafter, asshown in FIG. 9(a), an adhesion layer 10 a of about 2 nm in thickness isformed on the rail surface of the floating rail by the sputtering of Sior SiC, and then a protection layer 10 b is laminated thereon. Theprotection layer 10 b is formed with the diamond-like carbon (DLC) filmby the plasma CVD process and its thickness is about 20 nm or more, forexample, of about 30 nm.

[0061] Thereafter, as shown in FIG. 9(b), the resist 10 c is formed onthe area of the protection layer 10 b to form the projections 61 and 62.The resist 10 c is coated corresponding to the projections 51 and 62 inthe side of the air inflow end 5 and, if necessary, to the backwardprojections 63 and 64. Thereafter, the remaining portion not coveredwith the resist 10 c is etched by the ion milling process or the like,and thereby the projections 61 and 62 consisting of DLC are formed asshown in FIG. 9(c).

[0062] Moreover, as shown in FIG. 9(d), the surface of floating rail iscoated with the resist 10 d, except the area corresponding to the recess9. Thereafter, as shown in FIG. 9(e), the narrow portion 4 a is formedon the floating rail by etching the area corresponding the to the recess9 and then the resist 10 d is removed. With the processes explainedabove, the magnetic head slider as shown in FIGS. 2(a)-2(c) can beobtained. In the magnetic head slider, the floating rail including thenarrow portion 4 a is covered with the adhesion layer 10 a which is alsoworking as the protection film, and the projections 61 and 62 consistingof DLC are provided in the predetermined positions.

INDUSTRIAL APPLICABILITY

[0063] As will be apparent from above explanation, the present inventioncan provide the small flying height and can prevent the stiction to themagnetic disk.

[0064] The head slider of the present invention can realize the smallflying height while preventing the stiction to the magnetic disk.Therefore, the recording/reproducing sensitivity to the recording mediumcan be improved and therefore the high density recording can berealized.

[0065] Particularly, the magnetic disk drives have been greatly improvedin the recording capacity and is still required to further increase therecording capacity. From this point of view, the head slider of thepresent invention is very effective. Moreover, the present invention isalso effective not only to the magnetic disk drive but also to anoptical disk drive using the head slider.

What is claimed is:
 1. A head slider mounting a recording/reproducingelement and flying over a recording medium with the air flow generatedwhen said recording medium moves, comprising: a slider body having anair inflow end and an air outflow end; at least one rail projected fromsaid slider body and defining an air bearing surface which is extendedto the air outflow end; at least one projection formed on said rail andbetween the air inflow end and the air outflow end; and a recess formedat the air outflow end of said rail to make narrow the width of saidrail.
 2. The head slider claimed in claim 1, wherein the width of saidrecording/reproducing element at the surface opposed to the recordingmedium is formed narrower than the width of said rail at the air outflowend.
 3. The head slider claimed in claim 1, wherein said rail comprisesa couple of rails and said recess is formed at the air outflow end ofeach rail.
 4. The head slider as claimed in claim 3, wherein saidrecording/reproducing element is formed at the air outflow end of onerail, and the width of said one rail at the air outflow end is widerthan the corresponding width of the other rail.
 5. The head slider asclaimed in claim 1, wherein said recess isolates an area, where saidrecording/reproducing element is formed, from the air bearing surface ofsaid rail and forms said area like an island.
 6. The head slider asclaimed in claim 1, wherein said projection comprises a first projectionformed in the side of the air inflow end and a second projection formedbetween said first projection and the air outflow end.